The invention relates to a flow guiding body on a gas turbine combustion chamber for spinning an impinging air flow, consisting of at least one acutely tapering molded shell of an essentially conical design, whose surface area projection is formed by at least one straight line as well as an arbitrary curve connecting the end points of the straight line. The molded shell faces the air flow impinging on the outer side essentially with its tip.
From European Patent document EP-A-0 063 729, a comparable flow guiding body is known as an arrangement for inverting and mixing flowing substances.
On gas turbine combustion chambers, particularly for aircraft engines, so-called airblast atomizers are known which have two or more coaxial ring ducts through which the air mass delivered by the compressor flows with different spins. In this context, a mixing with fuel has become known. In this case, two air ducts are separated by a sharply tapering circular ring to which a fuel film is applied. The fuel film is driven by the air masses to the end edge of the circular ring and is atomized there. In the close area of the atomization edge, the fuel drop spray has a boundary-wake characteristic, which results in a poor homogeneity of the resulting fuel air mixture.
Furthermore, a flow guiding body which has an acutely tapering molded shell is known in connection with a fuel feeding system for a combustion chamber from European Patent document EP-A-0 619 456, and in connection with a premixing burner from European Patent document EP-A-0 619 457.
Also, on gas turbines it is known to feed the mixing air for the different combustion zones of a combustion chamber through plain or plunged holes in the combustion chamber wall. Frequently, this takes place in that the individual air jets which penetrate the different holes in the combustion chamber wall meet in a stagnation point and locally cause a high turbulence there. However, in the interior of the combustion chamber, hot gas situated in the interior flows around the blown-in air jets in the manner of a massive rod so that, in the area in which the hot gas and the admixed air meet, there will be no optimal mixing of air. A mixing occurs only in the boundary layer area between the admixed air jet and the hot gas. It is known that this so-called hot gas slip through the hole cross-section of a combustion chamber is relatively high.
For improving the mixing process of gases in or on gas turbine combustion chambers, so-called "delta wings" have also become known. In this respect, reference is made, for example, to European Patent document EP 0 623 786 A1 or U.S. Pat. No. 3,974,646. Such delta wings are sharp-edged bodies which divide an impinging flow field into two partial flows each having a swirl axis such that the swirl axes are convergent. The mixing processes which can be achieved in this manner are not completely satisfactory because of this convergent swirl formation.
It is therefore an object of the invention to indicate measures by which mixing processes of gases in gas turbine combustion chambers can be improved. In particular, non-convergent and preferably divergently extending swirl axes are to be generated downstream of the flow guiding body.
For achieving this object, the present invention provides a flow guiding body on a gas turbine combustion chamber for spinning air flow, consisting of at least one acutely tapering molded shell of an essentially conical design, whose surface area projection is formed by at least one straight line as well as an arbitrary curve connecting the end points of the straight line. The molded shell, essentially with its tip, faces the air flow impinging on the outer side. Advantageous developments and further developments are described herein.
The invention will be explained in detail by means of preferred embodiments .